Electron-discharge device



Sept. 11, 1928. Y

Y A. MAVROGENIS ELECTRON mscmaen DEVICE 2 Sheets-Sheet 1 Filed Feb. 21.1927 Sept. 11, 1928. I 1,684,104

A. MAVROGENIS ELECTRON DISCHARGE DEVICE Fil ed Feb..21. 1927 2Sheets-Sheet 2 '54 a-ya? l U J/JJJv 527/3.

atented Sept. 11, 1928.

.ARISTOTE MAVBOGENIS, OF MILWAUKEE, WISCONSIN.

ELECTRON-DISCHARGE DEVICE.

Application filed February 21, 1927. Serial No. 169,876;

I This invention relates to unitary electron discharge, devices andisparticularly directed to a device in which means are pro vided forvmaintaining a permanent negative potential on the controlling elementwith respect ,to the cathode of such unitary devices.

It has been the practice heretofore to insert a relatively small drybattery or storage battery or its equivalent C battery eliminator in thegrid circuit of a vacuum tube in order to maintain the grid at asuitable negative potential with respect to the cathode of such tubeswhen used as detectors or amplifiers.

In case of a vacuum tube amplifier when used at audio frequency with arelatively large ,output plate current, a C battery is inserted in thegrid circuit between the grid and the cathode of such amplifier in orderto maintain a permanent negative potential 2 of a suitable value on thegrid, such poten- ,tial being atleast equal to the manimum amplitude ofvoltage variation of tll8 1I1 COIl 1- ing radio-waves impressed on thegrid 1n order to secure distortionless, reception. Such vacuum tubeamplifiers are usually of the audion type known under the trade name ofpower amplifiers, and are usuallyused in the last stage of the audiofrequency amplification of the radio receiver. These tubes necessitate aG battery in the gr d circuit when their output plate current 15 equalto or above three to five milliamperes,

in orderto securedistortionless reception. The-tubes therefore requirenot only the usual filament and plate batteries, but also the additionalC battery, or else their equivalent battery eliminatorsf It is awell-known fact that the addition to any radio receiver of a thirdauxiliary C- battery or its equivalent G battery eliminator not onlyincreases the number of access" sories of such radio receiver, but alsonecessitates auxiliary busbar connections and binding posts'which thusproduce an in- .v

' tube.

batteries, and to provide a unitary electron discharge device which notonl avoids th necessity of both filament and p ate batteries or theirequivalent battery eliminators, but also eliminates the C battery or itsequiva lent C battery eliminator.

A further object is to provide a permanent means within the unitarystructure of thr electron discharge device for maintaining a permanentand suitable negative potential on the grid of the device.

Further objects are to provide means for impressing a permanent,suitable negative voltage on the controlling element of the un tarydevice by means which are perma nently associated with the unitarystructure of the device, and which do not require either renewals,adjustments, upkeep expense, or any additional element within the Thisinvention is particularly applicable to vacuum tubes of the general typedisi closed in my prior Patents, N o. 1,570,4a4 of January 19,- 1926,for Wireless apparatus,

and for electron discharge devices, N o. 1,f338,499, of August 9,1927;No. 1,616 914, of February 8, 1927; No. 1,629,171 of May 11, 1927, andmy copending applications for electron discharge devices, Serial No.145,940, filed November 3, 1926; and Serial No. 159,313, filed Jan. 6,1927.

Embodiments of the -invention are shown in the accompanying drawings inwhich Figure 1 is a diagrammatic view showmg one form of the inventionand disclosin'r particulqrly a unitary electron discharge de v1ce hav nga single wave rectifier; 5

Flgure 2 1s a view corresponding to Figure 1 showing the device adaptedfor double wave rectification;

Figure 3 is a perspective view part1 in section showing the physicalstructure of the tube, diagrammatically shown in Figure 2;

Figure/1 is a sectional View on the line 4 4: of Figure 3; Y, Y

Figure 5 is a diagrammatic view of a modified form of the invention; e tFigure 6 shows a modified form of the invention in which a vaporrectifier isemployed; i

in which a full wave vapor rectifier is used.

Referring to Figure 1, it will be seen that the device comprises aunitary structure whlch consists of an evacuated vessel 1 hav- V IFigure 7 shows a further modified .form 7 iio ing a base portion 2. Thevessel 1 is preferably of the high vacuum type and encloses a rectifier,indicated generally by the reference character It, a current limitingdevice, indicated generally by the reference character C, and an audion,indicated generally by the reference character A. Within the base 2 ofthe device which constitutes a permanent portion of the struc- 'ture aremounted the condensers and resistance, as hereinafter described, so thatthe device may be inserted in a tube socket or removed therefrom as aunit.

The device is provided with four prongs v indicated at 3, 4, 5, and.6,which extend outwardly through the base of the. tube, al-

though for convenience of illustration, they have been showndiagrammatically in their most easily illustrated positions in Figure 1.

The rectifier has an equipotential cathode 7 .and an anode 8. The anodeis connected directly to the prong 3 and from thence to one of thealternating current mains 9. The cathode is connected by means of theconductor 10 to the anode 11 of the current limiting device. The cathode12 of the current limiting device is connected by means of the conductor13 to one end of a resistance 14, as shown in Figure 1, to the upper endof such resistance. This upper end of the resistance is also connectedto an auxiliary binding post 15 accessible externally of the tube, asdescribed in detail in connection with Figures 3 and 4. At a suitablepoint along the resistance 14, the equipotential cathode 16 of theaudion A is connected,

the plate 17 of the audion being connected through the translatingdevice, such as the primary 18 of an inter-valve transformer to thepoint 15 and, consequently, to the upper side of the resistance 14.Consequently, the audion has impressed between its plate and cathode thevoltage drop between thepoint at which the cathode is attached to theresistance 14' and the upper end of the resists ance or the point wherethe contact or binding post 15, is attached. I The grid 19 is interposedbetween the cathode 16 and the plate 17 and is connected to one end ofthe secondary 20 of the input transformer, the

other end of the secondary being connected to the prong 4. Further, itis to be noted that, this prong. is connected through a variableresistance 21 to the other main 22 of the alternating current supplysystem.

I It is to beln'ot'ed that a storage condenser 23 .is connected betweenthe conductor 10 and the prong 4 and also it is to'be noted that theresistance 14 'isparalleled or bridged by means of the bypass condenser24. Further, it will be noted from a considerationof Figure 1 that theresistance. 14 and the bypass condenser 24 are both in reality bridgedaround the audion.

It is to be noted further that the lower audion.

end of the resistance 14 is connected to the common point of thecondensers 24 and 23.

It is to be noted further that filaments, as

indicated at 25, are provided for heating each of the eqnipotentialcathodes 7,12,.and 16, and that these filaments are joined in series,although obviously they could be joined in parallel, if desired, andhave their ends connected to the prongs 3 and 4. It is preferable toconnect these filaments in series as it has been found more readilypracticable to construct a filament so connected as to permit its directconnection to the volt alternating current mains.

It will be seen that current rectified by the rectifier R passes alongconductors 10 to the plate 11 of the current limitingdevice. Fromthence, current passes to the cathode .12 of such device. Further, it isto be noted that the storage condenser 23 is connected to the conductor10 and to the prong 4 and consequently stores up a part of thepulsations. The current limiting device, as illustrated in Figure 1 isof the thermionic type described in greater detail in my co-pendingapplications noted above, and in my prior patents. It is intended thatit be saturated at the minimum voltage supplied by thepulsatingunidirectional current so that the cur rent flow through thedevice is absolutely constant, irrespective of any variation of voltageimpressed thereon.

Current from this current limiting device passes through the resistance14 to the prong 4 and from thence to the other main. Further, it is tobe noted that the upper end of the resistance 14 is positive withrespect to the point at which the cathode 16 is attached. sired for theaudion may be obtained by selecting the point at which the cathode isconnected, as it is to be noted that the plate is connected through theoutput device with the binding post 15.

It is to be particularly noted also that by adjusting the point at whichthe cathode 16 is connected to theresistance 14 that the exact negativepotential desired upon the grid may be obtained) For example, the pointat which the cathode is attached to the resistance 14 is positive withrespect to the lower end of this resistance. end of the resistance 14 isconnected through the prong 4 and through the input device 20 to thegrid 19 and, consequently, the. grid is maintained permanently negativewith respect to the cathode 16 of the It will be seen that theresistance 14 and the condensers 23 and 24 are permanently carried inthe base of the unitary'device and that the device is provided with onlyfour prongs and with anauxiliarybinding 'post hereinafter described ingreater detail.

Further, fit will be seen that the device Consequently, the exactvoltage de- The lower is so constructed that it eliminates not only theA battery and the B battery, but also the (3 battery, or the equivalentC battery without the addition of any extra element within the evacuatedportion of the tube.

In the form of the invention shown in Figure 2, the same generalinventive idea is followed. The device is provided with the prongs 26,27, 28, and 29 and with the auxiliary' binding posts .30 and 31. -Thefilaments 32'are connectedin series and directly across the alternatingcurrent mains 9 and 22 through the variable resistance 21. In this formof the invention, the prongs 26 and 27 which are connected to the twomains are directly connected to the anodes 33 and 34 of afull. waverectifier. Further, the prongs 26 and 27 are bridged by the resistance35. The full wave rectifier is provided with an equipotential cathode 36which is connected by means of the conductor 37 with the anode 38 of thecurrent limiting device. Further, it is connected to one side of thestorage condenser 39' The cathods 40 of the current limiting device isconnected tothe anode or plate 41 of the audion and also to one side ofthe bypass condenser 42- and to the upper side of the resistance 43. Thelower side of the resistance and the other sidesof the condensers 39 and42 mentioned previously are connected by a common conductor 44 with thecenter point of the resistance 35. Y Further, it is to be noted that thebinding post 31 is connected to an intermediate point of resistance 43,pref-' erably adjacent its lower end as 'indicated, and that the bindingpost 30 is.

connected to the. lower end of the resistance by means of the commonconductor 44. The cathode 45 of the audion. is connected through theoutput device or translating device, indicated by the referencecharacter-46, to the binding post 31 and consequently to theintermediate point of the resistance 43. The grid is connected throughthe prong 28 with one side of the input secondary 47, the other side ofsuch secondary beingconnected to the] binding post-30, and consequently,to .the lower end of the resistance 43. It will be' seen, therefore,that the point at which the binding post 31 is connected to theresistance 43 and the point at which the-binding post 30 is connected tosuch resistance causes a negative potentialto be impressed on the gridof the audion and, consequently, such grid is maintained negative withrespect to the cathode of the audion. The full wave rectifier, ofcourse, rectifies both of the half waves of the alternating current andconsequently, a smaller storage condenser 39 may .be used than-with theform previously described. Further, the resistance 35 provides a neutralpoint for the return conductor 44. In both forms of the; invention notonly is the temperature of the filament controlled by the resistance 21,but also the voltage impressed on the audion is simultaneouslycontrolled by such resistance. 7 In the physical embodiment of theinvention disclosed diagrammatically in Figure 2, it will be seenparticularly from F ig ures 3 and 4, that the tube base 2 of the unitarydevice carries the several prongs and also is provided with a pair ofoutwardly projecting members or lugs 48 which carry the binding posts 30and 31. Further,

. the prongs 26,27, 28, and 29 project through the base 2 in the usualmanner. The evacuated vessel 1 is provided with an upstanding bridge 49which supports the several elements of the device. The particular formof cathode and filament used in this tube is illustrated particularl indetail in my Patent No. 1,629,171, of ay 17, 1927, for electrondischarge devices.

Any suitable means may be provided for connecting the binding posts 30and 31 with the respective conductors. For example, a brass or othermetal sleeve 50 (see Figures 3 and 4) may be embedded in the arms 48 andmay cont'act'with the screw of the binding posts 30 or 31. Preferably,the metal sleeve is hollow and the conductor 51 leading thereto may bereadily soldered, as indicated at 52. It is also preferable to roughenthe exterior of the sleeve 50 so that the insulating base portion 2 mayreadily grip such sleeve. It is to be distinctly understood, however,that other forms may be employed than. thefo'rms specified herewithwithout departing from the spirit of this invention. It is also to beunderstood that preferably the condensers 39 and 42, as well as theresistance 43 and 35, shown in Figure 2, are formed in a single block,as indicated at 53 in Figure 3', and that this block is mounted in thebase portion 2 of the device. preferable also to separate the block fromthe tube by means of a mica or other insulating washer 54, as indicatedin Figure 3.

With a tube constructed as illustrated, the usual type of tube socketmay be employed into which the tubeis inserted, as only four prongsareused, the auxiliary connections being furnished by the binding posts 30and It is preferable, however, to provide the auxiliary contacts in theform of auxiliary binding postsso that the device maybe insertedinstandard sockets Without requir- It is v ii'iglany'alterations and may,consequently, utilize and cooperatewith standard equip- 1 ment.

Referring to the form of the invention shown in Figure 5, it will beseenthat the device comprises the evacuated vessel 1 having the base 2.However, this vessel is divided into three compartments 55, 56, and 57.The compartment 55 contains a pair of relatively'small anodes 58 and arelatively large cathode 59 which encloses the anodes.

The compartment 55 contains a rarefied gas,

4 preferably of the helium group of such a pressure as to maintain agaseous discharge between the electrodes 58 and 59. The cathode 59 isconnected-by means of.a resistance 60 to the anode 61 of a voltage1imiting device The anode 61 of this device is relatively small and thecathode 62 thereof ,is relatively large and preferably cylindricalandencloses the anode. The gas in the compartment 56 is also of thehelium group and of such a pressure as to permit a gaseous dis argebetween the electrodes. It

- is to be noted in this form of the invention i the resistance 63through the resistance 60.

A storage condenser 65 is connected to the cathode 59 and also to thecommon conductor 64. A bypass condenser 66 is arranged parallel to theresistance 63. An intermediate point, preferably adjacent the lower endof the resistance 63 is connected to the cathode 67 of the audion, theplate 68 of the audion being connected through a translating or outputdevice 68" back to the upper end of the resistance 63. This connectionis through'one of the external binding postsg 68 similar to the bindingposts 30 and 31,

previously described. The other binding nish a bypass aroundthe audionto take care post 69 is connected to the lower end of the resistance 63.Further, the bindingpost 69 whichleads to the lower end of theresistance 63 or to the, commonconductorl64 is connected through theinput secondary 70 to the grid 71 of the audion. The audion,

.it will be noted, is contained in the separate compartment 57. Itwillbe seen fromthe connections described that a negative potential isimpressed upon the grid 71 of the audion or, in other words, the grid ismaintained at a definite -predetermined potential with reference to thecathode 67 of the audion. Also, it is to be noted that the device in'thecompartment whose anodes 58' are connected to the two supply mains 9 and22 through the variable therefore,

sistance 72 adjusts not only the voltage of the rectifier, but also thetemperature of the filamentand, consequently, the temperature of theequipotential cathode of the audion.

The metal selected-for the anodes 58 and '61- of the rectifier andvoltage limiting device and forthe cathodes 59 and 62 of the rectifierand voltage limiting device may be of any suitable type. Preferably,however, the

cathodes at each of these two devices is coated with an oxide orcompound of alkaline metals. I

It is tobe noted further that the voltage limiting device has a voltagecurrent characteristic which has a substantial portion thereof parallelto the current axis whereby a relatively great changein current flow mayoccur through the apparatus without appreciably altering the voltagebetween its terminals. Consequently when the rectifier suppliespulsating uni and charges thestora e condenser 65, such condenserdischarges through the resistance 60 across which a voltage drop occurs.The apparatus in the vessel 56 constitutes in efiect means for securinga constant difference in potential between the end of the resistance 60and the common conductor 64 and, con sequently, a constant upon theaudion. i The condenser 66 and resistance 63 furof any variations thatmay occur due to variations in the signals received by the audion and,consequently, variations in the demand made upon the apparatus.Referring to Figure 6, it will be seen that a further form of theinvention has been shown in which a vapor rectifier is employed. By theexpression, vapor rectifier, it is intended that either gaseousrectifiers or strictly vapor rectifiers be included.

directional current voltage isimpressed In this form of the invention,the rectifier comprises a vessel 74 of high heat resistingcharacteristics and of good dielectric properties and of non-porousmaterial, such for instance as quartz, silica, glass, etc., and ishermetically sealed, An anode 75 is sealed in the upper portion of thevessel 74: and in' the lower bulb-like portion an electrode 76 ispositioned. -The lower bulb-like portion preferably contains a cathodeof relatively low melting point or else one which emits vapors at arelatively low temperature, such vapors being the ionizing agents in therectifier. A pool of mercury may be used or else other materials, such'as alkali metals, for

. example, potassium, sodium, rubidium, caethe conductors to theelectrodes 75 and 76 are relatively rigid so that they will act assupports for the rectifier.

The cathode is connected by means of the conductors 78 and 79 to theplate 80 of the current limiting device and to one side of the storagecondenser 81. The other side of the storage condenser is connected bymeans of a conductor 82 through a variable resistance 83 to the othermain'84.

The vessel of the rectifier has a central enlarg'ement 85 and twocoatings 86 and 87 separated-by such enlargement. The coatings may beformed of electrically conduct- I ing and electroionically activematerial as described in my copending application, Serial No. 150,644,filed, November 26, 1926,. for gaseous discharge device; and Serial No.159,313, filed January 6, 1927. v v

The current passes from the anode 80 to the cathode 86 of the thermioniccurrent limiting device and passes from the cathode 86 through theconductor 88 to one side of the bypass condenser 89, and bypassresistance 90.

The other side of the condenser 89 and resistance 90 are connected tothe conductor 82. From the conductor 88 current passes by way ofconductor 91 to one side of a translating device, such as the primary 92of a transformer. The other side of the primary is connected tothe-plate. 93 of the audion, such audion having a grid 94 and thecathode 87 previously described. The cathode 87 is connected by means ofthe con ductor 95 to a point on the resistance 90" near its lower end.Further, it is to be noted that the grid 94 is connected through thesecondary 96 of a transformer to the lower end of the resistance 90. Inthis manner, a negative potential isimpressed upon the grid and the gridis maintained negative with respect to the'cathode of. the audion. Inthe form shownin Figure 7 substam tially the same arrangement isfollowed except that the rectifier is a fullwave recti fier. Further,the cathodes 97 and 98 of the current limiting device and audionrespectively, are shown as separate metal mem bers and are preferablycoated with a ldw' electron aflinity oxide. Obviously, either formofcathode, viz. the one previously described or the one just described,may be used on either the single or full wave'rectifier, withoutdeparting from the spirit of the invention. I

The rectifier vessel 99 has an electrode 100 sealed in its bulb-likelower end and a pair end. The anodes are connected to the mains 103 and104 through a variable resistance 105. Preferably, a heating resistance106 is of anodes 101 and 102 sealed in its upper connected across theconductors leading from the anodes 101 and 102 and further, a resistance107 is bridged thereacross. The

center point of this resistance is connected to one side of the storagecondenser 81 and bypasscondenser 89 and bypass resistance 90. Theremaining connections are the same as those described for Figure 6.

This last form of the invention provides.

for full" rectification and obviously a smaller storage condenser may beemployed. i

It will be seen that a novel form of unitary electron discharge devicehas been provided by this invention which is so constructed that itisadapted for energization wholly from alternating current mains and notonlysupplies energy for heating the several cathodes of the device andfor furnishing current to the plate of the audion, but also furnishesthe necessary difference of potential between the grid of the audion andthe cathode ofthe audion, so that the apparatus may function at the mostadvantageous portion of its characteristic curve. In other words, thisdevice insures distortionless reproduction and does not require anyadditional' C battery or any auxiliary apparatus whatsoever. Instead,the device is a com plete and self-contained unit and may be connecteddirectly to-the input and output portions of the system. and may bedirectly supplied from commercial alternating cur rent mains.

Although the invention has been described in considerable. detail, suchdescription is intended as illustrative rather than limiting as theinvention may be variously embodied and as the scope of such inventionis to be determined as claimed.

I claim: 1. A. unitary electron discharge device ineluding an evacuatedvessel, an audion mounted within said vessel-and-having a platea-Icathode-and an interposed grid, a rectifiermounted wlthin said vesselfor supplying energy to said audion,'-means carried byand forming- 1aunitary portion of-said device for impressing a negatlve voltage on saidgrid wit reference to the cathode of,

said audion,- and means for smoothing out the pulsations in the energysupplied by said rectifier.

2. A unitary electron discharge device adapted to be energized from asource of alternating current including an audion having a plate, acathode, and a. grid, a rectifier for supplying said audion, an energycontrolling device for smoothing out the pulsations'of energy suppliedsaid audion by said rectifier, and means for maintaining apredeterminedvolt-age difference between said grid and cathode, said audion,rectifier, and voltage maintaining means being permanently carried byand forming a unitary part of said electron discharge device.

3. unitary electron discharge device including anv evacuated vessel, anaudion mounted'within said vessel and having a plate, a cathode and aninterposed grid, a rectifier mounted within said vessel for supplyingsaid audion, means for smoothing out the'pulsations of energy suppliedby said rectifier, and a resistance bridged around said audion andhaving a portion thereof connected with the'grid of the audion for.

maintaining a definite predetermined voltage difierence between the gridand the cathode of said audion. v

4. A unitary electron discharge device including an evacuated vesselhaving a base permanently attached thereto and provided with terminals,an audion mounted within said evacuated vessel and having a cathode, aplate and an interposed grid, a rectifier mounted ,within said vesselfor supplying said resistance being located in the said base,

and connections leading from said terminals to the electrodes of theaudion, rectifier, and to said resistance.

In testimony that I claim the foregoing I have hereunto set my hand atMilwaukee, in the county of Milwaukee, and State of Wisconsin.

ARISTOTE MAVROGENIS.

